One of the earliest efforts at providing health protection for urinals was to use a solid block of paradichlorobenzene (PDB). These blocks were not positioned in the urinal in any particular way. Rather, they were merely tossed into the urinal. Since PDB sublimed at room temperature, it had a characteristic odor in use. However, PDB is substantially insoluble in water. As a result, the PDB evaporated continuously, rather than being dispensed at the time of flushing. As the blocks evaporated whether or not there was a need for the PDB, the blocks required frequent replacement. Because of the relatively rapid, continuous attrition by evaporation, custodial personnel could miss a needed replacement. In that case, the urinal would have no protection. In addition, since PDB is highly crystalline, the blocks tended to crack in use. The small pieces would then be either flushed away or lodged out of their position in the urinal where they would not be able to evaporate causing clogging of pipes.
Later, perfumes and germicides were added to PDB blocks. This improved the ability of the blocks to provide some cleaning and odor-covering properties. However, the blocks still sublimed at room temperature and were insoluble in water. The problem of unnecessary use at some times, followed by no use at others, was not solved. There also remained the problem of non-uniform distribution of the chemical, since the perfumed PDB blocks were still merely thrown into the urinal, and as a result sometimes cracked.
Another approach was to anchor PDB blocks by means of a wire loop hooked over the edge of the urinal or toilet. Also, exposed blocks have been secured to a plastic screen backing. Neither of these methods prevented cracking or subliming.
PDB or urine-soluble chemical blocks have been provided in a two-piece assembly. These two pieces include a separate screen and an open mesh cup secured to that screen. This did not solve the problem of continuous sublimation in the case of a PDB block placed in the screen mesh cup. In the case of fluid-soluble chemicals, there remains the problem of wasteful attrition of the chemical by the direct action of the urine impinging on the exposed blocks. Introduction of excess chemicals into the water supply also may aggravate water pollution.
In all of the aforementioned methods, the blocks and holder parts were manufactured separately and then assembled in expensive, multistep operations.
A disposable dispenser assembly for fluid-soluble chemicals that must slowly be released at prescribed times, and a method of manufacture of the chemicals and the dispenser assembly, was disclosed in U.S. Pat. No. 3,824,633 to E. Van Vlahakis, one of the co-inventors of the present invention. In addition, a toilet bowl dispenser assembly for controlled release of bactericidal, deodorizing agents from a solid type cake was disclosed in U.S. Pat. No. 4,096,593 to Vlahakis. Other inventions relating to urinal and toilet bowl disinfectant blocks include U.S. Pat. No. 4,604,357 to Callewaert et al., U.S. Pat. No. 4,722,801 to Bunczk et al., and U.S. Pat. No. 4,911,858 to Bunczk et al.
However, the present invention is an improvement over the prior art. The urinal block composition of the present invention includes the addition of a proteolytic enzyme (preferably protease), and this marks the first time a specific enzyme that targets proteins has been successfully added to a urinal block system with a pH below 4.0. This discovery is important because it allows the proteolytic enzyme to be encapsulated into a water activated, pre-measured dosage that is released with each flush of the urinal or toilet. In addition, it allows the proteolytic enzyme to work over a long period of time in a stable environment. The lowering of the pH does not have a detrimental effect on the proteolytic enzyme or germicide components. The higher concentration of acid also allows the product to neutralize more urine bases than before, and provides the added benefits of cleaning and shining of the porcelain fixtures.
The dispenser assembly of the present invention is also an improvement over the prior art. Previously, urinal blocks, with or without screens, were placed beside or on top of stainless steel strainers found in urinals. Such placement is neither aesthetically pleasing nor efficient, since the urinal block and/or dispenser could easily be displaced. However, one embodiment of the dispenser assembly of the present invention provides for an oval-shaped dispenser having an inner hollow design that allows the dispenser and retained urinal block to fit around a stainless steel strainer, without impeding the purpose of the strainer. In addition, the hollow sphere has elongated perforations in it to allow for the passage of liquids, for aeration, and for aesthetic purposes. A perforated flange surrounds the urinal block and hollow sphere and serves to support the dispenser in the desired location within the urinal while also serving to allow effective drainage of the urine. Thus, the present invention overcomes the deficiencies associated with the prior art by providing an improved urinal block composition and dispenser assembly that sanitizes and deodorizes urinals or toilets in a selective manner, is easily manufactured and assembled, and is long-lasting.